Clay WellsTable of Contents
1. Intro
2. Equipment
3. Preparation
4. Shooting
5. Processing
6. Technical Details
7. Conclusion
Intro
|Cano n 40D | ISO 100 | 17mm | 30 sec | f/7.1 |
Big thanks to the group for asking me and allowing me to share this. There are quite a few shooters in this group who create some really amazing long exposures, so I was honored when approached for this. I hope you find what I have written to be informative, that it generates some good discussion, and that you all enjoy reading it. Further, I hope it motivates you to get out and try some long exposures on your own.
I have always been fascinated by long exposures and how motion translates onto film or a digital sensor. It is intriguing how a 5-second exposure during daylight can turn moving people into ghosts or how a 30-second exposure can make them disappear completely. Night-time long exposures are often colorful and eye-catching especially if the subject is a city or moving traffic or reflections on a body of water.
There are many subject and scenes that lend themselves nicely to long exposures. In this Session I will focus mainly on traffic streak long exposures made during the “blue hour”, also known as twilight, that little window in the morning before the sunrises when the black sky is just starting to get some color and that corresponding window after the sun has set. For me, the ideal scene is one where there is interest in the sky like low-lying, thin, wispy, fast-moving clouds with clear air above. These conditions are rare and as my luck usually goes, tend to occur on mornings when it’s not practical or possible for me to shoot. Needless to say, I have many more outings under my belt than keepers in the portfolio.
Whenever everything does work out though, the results can be very satisfying.
1. Equipment
Mandatory:
• Camera
• Tripod
Optional:
• Filters
• Remote shutter release
• Flashlight
• Phone?
Mandatory stuff:
At the very least you will need a camera (obviously). I use a digital 35mm SLR which allows me to control exposure, aperture, ISO, etc, but there may be many non-SLR cameras that allow this sort of control as well. No matter the camera you use, you must have the ability to:
(1) to shoot exposures of at least 3-5 seconds and have the ability to blend images in post-processing
or
(2) shoot exposures as long as 30 seconds or longer.
Ideally, you will also need a tripod. While a flat, sturdy surface may work as well, I don't recommend it. Just get a tripod even if it's a cheap one. Hand-holding is absolutely out of the question.
Optional Stuff:
Filters - you really don't need any filters, and I have taken quite a few shots with none, but there are times when they do allow for some additional creativity. I typically use a circular polarizer to control glare and reflections off of buildings and sometimes a neutral density (ND) filter to extend exposure time if I'd like to capture the motion in the clouds in the sky. Many folks initially think that a neutral density filter makes the image dark or under-exposed. They don't - when used correctly they simply reduce the amount of light entering the lens thereby requiring you to shoot at (1) a wider aperture or (2) a longer shutter speed. But the resultant image, if correctly exposed, should not be dark or underexposed in any way.
The ND filter that I use is a 6-stop, but these come in many other flavors. There are one and two-stop versions and even a 10-stop. I could go broke buying filters. Singh-Ray makes a vari-ND that allows you to dial in 2-8 stops of neutral density. This would make composing the scene much easier since it’s almost impossible to even see through the view-finder when the 6-stop is attached. The problem is the vari-ND is about $400.
I use B+W brand filters which are screw-in type and are stackable. So when I combine my 6-stop ND and circular polarizer, I am getting about 7-8 stops of neutral density since the polarizer provides some as well.
In section 3 I will touch on how I decide when to use the ND or not.
Remote locking shutter release - using this will help reduce camera shake and will allow you to shoot in "bulb" mode and get exposures that are longer than 30 seconds. But it has to have a lock.
Flashlight (torch to some folks) – I carry one in my bag. I probably don’t have to go into detail as to how practical one would be on a pre-sunrise/post-sunset shoot.
Smart phone (iPhone) for entertainment while the long exposures are being made. I don’t recommend calling friends at 5:30 AM – they may decide to find a new friend, but if the phone has internet/game applications, it can help pass the time. Especially when the pre-sunrise light is not all that exciting.
2. Preparation
Preparation is very important. While the shots are easy to make with few variables to deal with, the light changes fast, very fast. In fact from my experience the ideal light typically takes place in about a 10-15 minute window about 30 minutes or so before sunrise. For me the “moment” is that little window when there is some color in the sky but not enough light hitting the streets and traffic to drown out the headlights and taillights. Once you get out and try these, you will know when the shoot is over. Once it becomes bright enough to read without a flashlight, it’s too bright.
I always scout out a location well before I actually shoot it. For a morning shot, I typically like to shoot facing the eastern sky, allowing me to take full advantage of that blue hour light in the east. If it's an evening shot, I like to find a scene that allows me to shoot toward the western sky. It’s a good idea to actually compose the scene during daylight hours noting all the elements and paying attention to which ones are potential distractions, which ones can be cloned, and which ones are likely to become less prominent in the pre-sunrise/post-sunset darkness.
In the shots below, note how the streaks lack real pop. I have learned that a couple of things seem to affect this. Shooting more straight-on seems to increase their prominence. This was shot well off to the side of the scene. Another thing that really robs from the streaks is the presence of street lights. In fact, they can literally kill the shot. So when scouting a location, pay attention to this. In some areas they are so bright that it's nearly impossible to get the desired effect.
| Canon 40D | ISO 100 | 17mm | 25s | f/16 |
| Canon 40D | ISO 100 | 23mm | 30s | f/10 |
Punctuality cannot be over-stressed. The sun won’t wait while you are stumbling out of bed or fiddling around with your gear, so find out what time the big event is and get there early. Shooting at sunrise or sunset will of course require you to know the exact time of the big event. In case you are not aware of it, the longest day of the year, June 21 has the earliest sunrise and latest sunset. The shortest day of the year, December 21, has the latest sunrise and the earliest sunset.
In the winter in Little Rock when the sun is rising fairly late, the morning temps are often in the teens and the wind can be brutal (to me anyway), so find out what the weather is going to be like and dress appropriately. In some cases you may have to park and walk a good distance to the shooting location making a return trip to the car unpractical, so carry that jacket with you even if you think you may not need it. Get some good gloves too or invest in one of those cold weather camera systems. It is basically a pair of mittens that somehow fit over the camera body and allow you to access all the controls. I tried fingerless gloves once and they only seemed to accentuate the numbness in my finger tips.
Lastly, since I typically shoot pre-sunrise, there are a few things I usually do the night before. These include things like making sure the camera bag is packed and ready to go, memory cards available, batteries charged, lens that I am going to be shooting with is attached, ISO is set back to 100 (or whatever its lowest possible setting is). These sound like little things, but the less you have to remember at 5:00 AM the better!
3. Shooting
The hardest part of these shots for me is getting out of bed, especially when it's January and it's 15 F (-9 C) outside and my spot next to my wife in said bed is warm and cozy! But they say, “One must suffer for one’s art”! Once up and out of bed though the rest is pretty easy. Fun too, if you have good skies and good early morning color in the sky. Get to the spot and set up. I usually find a single composition at a previously scouted location and shoot it the entire time. The reason is that since the ideal light doesn't last all that long, the chances of getting more than 2 comps are relatively slim. So just pick one and go with it.
I try my best to compose the scene carefully and commit to it. In other words, once I have started shooting, I keep the camera/tripod position as still as possible. By not making any changes/adjustments I stand a better chance of being able to blend a couple images in post a lot easier. Blending 2 or more images will allow me to create a final image that is evenly exposed in the sky and the traffic and one that has full streaks of light trails in all lanes of traffic.
I recommend taking several test exposures to get an idea of how much you should compensate (under/over) on the exposure. Once you've got the correct exposure settings, it's time to begin shooting through the good light until the show is over.
If you use a dark neutral density filter, it is a good idea to compose the scene without it, then switch to manual focus or lock the focus, then attach the filter for shooting. There is a good chance that you won't even be able to see the scene with the ND attached and the camera will probably have a tough time focusing. If your lens doesn't focus internally, be careful when attaching the ND filter so as not to turn the focus ring, or the polarizer for that matter.
You will also want to cover the eye-piece while your exposures are being made to prevent light from entering the back of the camera. Not doing so will throw the metering off. If you don’t believe it, set up and do this: look through the eye-piece from about 6 inches and note the shutter speed. Then really get your eye pressed up against the eye-piece and use your hands to block light coming in from the sides and note the shutter speed. Big, big difference! And to minimize camera shake I also recommend using a remote and/or the self-timer and mirror lockup functions if your camera provides it. Anything you can do to preserve the sharpness of the image the better.
Shoot for the streaks first (the lower half of the shot), the sky later (top half). Once you have made your test shots and determined the appropriate exposure settings, it’s time to start shooting. If you can get 15 to 30-second exposures without the ND, I recommend not using it for the traffic shots. Ideally the light in the sky is still approaching “ideal”, so start getting some good traffic shots. You can worry about the sky in a few minutes. Watch the traffic closely. There isn’t much of it in Little Rock at 5:15 AM and there are some occasions when a 30-second exposure won’t net too many streaks. Pay close attention to the access roads, exit ramps, and side streets. When you see a car on these less-used streets, make sure to capture it. Remember, you are going to blend these in post to make it look like every street was full of cars and light.
Once the light in the sky starts getting nice, carefully attach the ND if you want more than 30 seconds on the shutter speed and begin capturing shots of the sky. You may need to compensate your exposure so shoot a test shot or two and adjusts accordingly. And be glad this is digital and not film! At the end of this is a discussion on how to determine the exposure and shoot 30-plus second exposures in bulb mode. I figured I’d save the boring part until the end. Some people may be perfectly happy shooting shorter exposures.
4. Processing
Creating more traffic than there really is:
"Another Early One"
| Canon 40D | ISO 100 | 20mm | 30s- traffic/170s- sky | f/7.1 |
"The Worm"
| Canon 40D | ISO 100 | 21mm | 30s | f/10 |
I use Photoshop Elements 6 for editing. Typically I will blend an image or two in order to get full traffic in all lanes including the access ramps in the above. You don't need bumper-to-bumper traffic, but having light in every lane is typically more appealing. So while shooting, I try to pay attention to the traffic and make sure to capture the scene whenever a car is approaching those access ramps and side streets. In Elements I simply open the two images I want to blend, use the move tool (V), hold down the shift key and drag one image onto the top of the other. This will ensure that both images line up assuming you composed without moving the camera. Set the blend mode of the top image to "lighten".
The top shot above is a composite of several shots for the traffic ranging from 20-30 seconds and a 170-second exposure for the sky to get the streaks in the clouds. Skip to the bottom to see how to correctly determine the exposure on a 30+ second exposure. It's somewhat technical and I was hoping not to put anyone asleep until the end of this.
The four "non-keeper" images below were shot under fairly un-interesting skies and were edited very little, but they illustrate two things:
(a) The blending to get more light streams into a the final image
(b) What these types of shots look like when shooting at relatively short shutter speeds. Whether you like the effect or not of course depends on personal preference.
Final:
Other early morning traffic streak shots:
Good Morning (Fire Eater)
| Canon 40D | ISO 100 | 17mm | 30s | f/5.6 |
The above is actually my most "interesting" image according to Flickr and is still very popular in terms of daily views and such. This happens to be a single image, no blends. I was lucky enough to get enough motion in the clouds in 30 seconds. This is rare though.
The shot below is another single image. I was lucky enough to get this on my 2nd outting. It was very cold that morning - I guess this was my reward.
"This City Comes to Life"
| Canon 40D | ISO 100 | 50mm | 30s | f/11 |
5. Other non-traffic-streak evening/night shots that are fun to take
Even though many of the photos I posted here focus on traffic-streak shots, shooting at twilight or dusk, in the blue hour, is quite fun. Here are a few other shots I have taken during these times:
This is the street-car that runs a loop in downtown Little Rock. This was only a 1 or 2 second exposure, but it was long enough to blur the car and give an interesting effect.
| Canon 40D | ISO 160 | 17mm | 1.60s | f/4 |
Another favorite subject of mine I shot under some fast moving clouds one evening and with a 6-stop ND:
| Canon 40D | ISO 100 | 50mm | 30s | f/7.1 |
This is an evening shot the Arkansas State Capitol building dressed up in Christmas lights. No motion of any kind here, but this to me illustrates the blue hour at its most beautiful. Ten minutes later, this shot would lose all interest for me, as the sky would have been totally black.
| Canon 40D | ISO 100 | 17mm | 4s | f/8 |
Morning shot of the Capitol that illustrates both (1) the beauty of the blue hour in the sky and the window reflections and (2) photographer's luck, something I don't have too often, in that traffic streak that resulted from a maintenance vehicle passing in front of the building.
| Canon 40D | ISO 100 | 17mm | 30s | f/5.6 |
Sometimes it's possible to capture motion in the sky after the sun is up in the morning, but you will need both lots of neutral density and fast moving clouds.
| Canon 40D | ISO 100 | 17mm | 30s | f/11 |
Waterfalls are another favorite subject of mine. Someone could do an entire session on these subjects. Best to shoot these on cloudy, overcast days. While this exposure is 8 seconds, that is really more than long enough. In fact, in some cases, it may be too long. At this length you run the risk of capturing movement in the trees. Typically an exposure of 1/2 second or more is all you need. Of course there are ways to fix the movement in the trees if you feel like blending a couple images.
| Canon 40D | ISO 100 | 17mm | 8s | f/11 |
6. Boring discussion on how to calculate exposure manually
If I use a neutral density filter, it is typically a 6-stop. In the pre-sunrise darkness at a desirable aperture of f/8 to f/11, the camera is typically going to display the blinking "30 sec" or equivalent message, for shutter speed when this filter is attached, indicating there isn't enough light to get the correct exposure. To determine the correct exposure, I usually open the lens up all the way with the filter attached. If I'm lucky enough to get something other than the blinking "30" at f/4, then I'm in good shape - this is a little easier to calculate than if I were to still get the blinking "30".
For reference, each interval below represents one full stop of light:
f/2 - f/2.8 - f/4 - f/5.6 - f/8 - f/11 - f/16 - f/22 - ??? (my sensor is too dirty to worry about it at this point!)
In aperture priority mode, say for example that at f/4 the resulting shutter speed is 25 seconds. From f/4 to f/5.6 is one full stop and for every full stop down (going from wider aperture to smaller) you have to double the shutter speed. So the shutter speed at f/5.6 needs to be 50 seconds. The next full stop on the aperture is f/8. Shutter speed at f/8 should be 100 seconds. The next full stop, f/11, would need 200 seconds. F/16 would require a 400 second exposure.
If you open the lens up all the way and still get the “low light” indication, then you will have to remove the ND and observe the shutter speed at the desired aperture setting. Say for example, without the ND, you get 2 seconds at f/8. When you attach the filter, you are cutting 6-stops of light. It’s like stopping down the aperture 6-full stops. To compensate for that, you will need to double the shutter speed 6 times, resulting in a shutter speed of 128 seconds.
It’s best to experiment with and get an understanding of all of this before you are out shooting, so play around with it when it doesn’t matter. The math is simple, but at 5:30 in the morning, when time is of the essence, it can be easy to make a simple mistake. One that might cost you “the shot”.
So decide which of these you want, switch to "M", manual exposure mode, set shutter speed to "B" or "bulb", aperture to desired setting based on your calculation, use the locking remote shutter release and make the exposure. Just make sure that if you go with a 400 second exposure that your calculation is right and that you remember how long it has to be after you lock the shutter open! There is nothing worse than making a 7-8 minute exposure only to discover that it is either under or over-exposed. Write down the exposure time too if needed. In “bulb” mode you have to physically lock the shutter open, then unlock it at the appropriate time. It’s not all that hard to forget how long the exposure needs to be midway through it. Check your camera – it may display the elapsed time on the LCD. If not, use a stopwatch.
I recommend turning off the in-camera noise reduction, since it takes as long to perform the noise reduction as the camera took to make the exposure.
I shoot RAW, but if you shoot JPEG you will have to experiment with the white balance settings. I typically use the setting that the camera chooses when making the conversion. You may have to de-saturate the yellows depending on how harsh the artificial street lighting is in your area.
Conclusion
Well. You've made it to the end! The great thing about digital is that it affords us the opportunity to experiment with all these techniques. I seldom tried any of this in the film days. I just couldn't afford to. I have complete respect and admiration for those that did though.
So, get out this evening or tomorrow morning and give that "blue hour" a try!
**Little Rock, AR, home of former US President Bill Clinton, while he was Governor of Arkansas.
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